The purpose of this case-control study is to characterize the prognostic indicators, including HIV infection, for the positive outcome of sustained heroin cessation among persons with a prior history of chronic heroin use within economically disadvantaged, predominantly racial/ethnic minority neighborhoods in New York City (NYC). With drug use as a major risk factor for HIV and a chronic relapsing condition, identifying factors that promote sustained cessation can be key to enhancing HIV prevention and treatment efforts. Also unknown is what happens with sexual risk after short and long term cessation;an important but understudied consideration. Previous studies that have described patterns of cessation have been limited for several reasons. First, while much work has been done on relapse and cessation, the literature is sparse on long- term effective cessation. Second, most studies have sampled from treatment settings which misses persons who cease use without treatment. Third, previous research has not investigated the possible impact of determinants at multiple levels, including initial circumstances of cessation (e.g., influence of incarceration, family, etc.), potential influences of individual-level factors (e.g., social support, network characteristics) and one's neighborhood context (e.g., availability of drugs, density of AIDS cases). Post treatment relapse is more common in disadvantaged communities where persons return to settings with cues for drug use, however a proportion sustains cessation;characterizing neighborhood factors that contribute to this remains understudied. To identify factors associated with sustained cessation, we will recruit 1800 heroin using individuals utilizing venue- and respondent-driven sampling in 36 NYC neighborhoods. Eligible individuals will be those aged >27 years with a history of heroin use at least five years before interview. Eligible and consenting participants will undergo structured interviews include a year by year recall for the prior 6 years as has been used successfully in earlier studies. For analyses, cases will be defined as former heroin users, i.e., non-use at interview (N=744). Two control groups are specified: (1) heroin users who used continuously through past six years, (N=527) and (2) relapsed heroin users who were abstinent sometime in the past 5 years but who subsequently relapsed to drug use (N=527). Cases (sustained cessation) and controls will be frequency matched on age and age at heroin initiation ([unreadable]2 years) during analysis. Determinants of sustained cessation will be assessed using conditional logistic regression and hierarchical modeling. Data from this study can be used to identify modifiable factors that can be subjected to individual, group or policy intervention to promote sustained cessation from opiate use. Additionally, we will consider heroin cessation as an "exposure" by examining the relation between cessation and high-risk sexual behavior.